var s = [String:Float]()
var s = Dictionary<String,Float>()
var s = ["a":1,"b":2]

strings["a"] = "AZ"
strings.updateValue("AX", forKey: "a")  
strings.removeValueForKey("nope")

for (key, val) in strings {
    print("\(key): \(val)")
}

for key in strings.keys {
    print("KEY: \(key)")
}

for val in strings.values {
    print("VAL: \(val)")
}

// all key
let keys = Array(strings.keys)

// all value
let vals = Array(strings.values)

// clear
strings = [:]